Previously: #20052 (review), #20052 (comment)

Describe the bug

When editing a paragraph link on a narrow viewport, the popover may stretch beyond the edges of the screen.

To reproduce

Steps to reproduce the behavior:

1. (Prerequisite) Shrink screen (manually or via emulation) or use mobile device
2. Navigate to Posts > Add New
3. Insert a paragraph
4. Click in the block toolbar to insert a link
5. Note that link editor may stretch beyond the screen edges.

Expected behavior

Link editor shows within the constraints of the viewport.

Additional context

For solution:

• Consider how this behaved previously.
• See if there are fixed or minimum widths in any of the relevant components that may be the cause of this issue (LinkInlineUI, LinkControl, URLInput)
• Consider centering the popover on small devices, rather than opening to the right.